def validate_menu_categories(value):
    required_catogories = ["Appetizers", "Main Course", "Desserts"]
    for c in required_catogories:
        if c.lower() not in value.lower():
            raise ValidationError(message "The menu must include each of the categories "Appetizers", "Main Course", "Desserts".")
    
        
class Menu(models.Model):
    name = models.CharField(max_length=100)
    description = models.TextField(validators=[validate_menu_categories])
    restaurant = models.ForeignKey("Restaurant", on_delete=models.CASCADE)